Process for treating fibrous plant tissues



Patented Feb. 11, 1930 UNITED STATES PATENT OFFICE DINSHA'W BATTONJ'I NANJI, OF HEADINGLEY, LEEDS, ENGLAND, ASSIGNOR OF ONE- HALF TO DUNCAN MAYIBURY STEWART, OF LONDON, ENGLAND PROCESS FOR TREATING FIBROUS PLANT TISSUES No Drawing. Application filed March 9, 1928, Serial No. 260,554, and in Great Britain Apri1 29, 1927.

This invention relates to a new or improved process of treating fibrous plant tissues for the production of a lustrous or silk-like fibre suitable for spinning.

The object of the invention is the production from bast tissues including such fibrous vegetable material as flax, hemp ramie and the like of a fibre not only possessing a texture and lustre equal, if not superior to those of the cellulose products known in commerce as artificial silk, but also having greater tensile strength than such products and producible much more economically.

Broadly, the improved process for the production of lustrous fibre consists in treating the vegetable fibre or plant tissue either in the raw or unworked condition, or after it has been spun or woven, with an alkaline reagent and heating, preferably, under a relatively high pressure, for instance from 6 to 10 atmospheres, which may be developed by heating the liquid under confinement sufliciently to produce such pressure, the treatment under pressure being continued for a comparatively short time. By means of this treatment, it is possible to remove pectin and other impurities with which the actual fibre itself is impregnated and so produce the silklike lustre characteristic of the fibre obtained, without in any way impairing its inherent natural strength.

As an example of the application of the process to a specific fibrous raw material, the following method of treating hemp is given. Hemp in the form of hank or yarn is heated in an autoclave, with a suitable volume of a 1 to 4 per cent solution of caustic soda, the treatment being effected at a pressure of 10 atmospheres or thereabouts, which may be produced by heating under confinement, continued for a period of from to minutes duration.

The material thus treated is then preferably washed to free it from the major part of the alkali and bleached inthe usual manner.

The bleaching operation may, however, be effected prior to the treatment with the alkaline reagent.

The resultant product is found to have a lustre and texture comparable with that of artificial silk, but is of greater strength than artificial silk, and it may be woven or otherwise worked in ordinary textile machinery and generally used in the manner of an ordinary silken fibre or fabric. Further, fabrics of the material obtained are subject to less rapid deterioration in laundering than fabrics of ordinary artificial silk.

The actual conditions employed, such as time of treatment, strength of alkaline reagent and temperature and pressure at which the operation is carried out may be varied according to the nature of the raw material, and other suitable alkaline substances than caustic soda, such as sodium carbonate, sulphide or silicate may be employed.

It will also be seen that the improved process may quite well be applied to such raw materials as flax which require a preliminary retting or equivalent process for the resolution of the plant tissues into its individual fibres.

I claim 1. A process for the production of a lustrous fibre consisting in heating hast tissues with a caustic soda solution of l to 4 per cent concentration, the treatment being effected at a pressure of approximately 10 atmospheres and continued for a period of from 2060 minutes duration.

2. A process for the production of a lustro us fibre, consisting in the treatment of bast tissues with an alkaline reagent and heating under a pressure of from 6 to 10 atmospheres for a comparatively short time.

In testimony whereof I aflix my signature.

DINSHAlV RATTONJ I NANJI. 

